DLINK: Dual link based radio frequency fingerprinting for wearable devices

Exploiting unique wireless channel characteristics like signal strength for secret key generation has been recently studied by researchers. These schemes are lightweight and suitable for resource constrained wearable devices. However, a major drawback of existing schemes is that the successive channel samples with small sampling interval will have high correlation in time. This reduces the entropy and bit rate of keys. In this paper, we present dual-link based Radio Frequency fingerprinting solution - DLINK, which dynamically identifies the suitable multipath link to generate secret keys with improved entropy and bit rate in fast as well as slow fading channel conditions. We conduct an extensive set of experiments with real sensor devices mounted on subjects in multiple indoor environments. Our results show that, DLINK reduces the correlation of successive channel samples by 67%, and has 5 times higher bit rate, and improved entropy in all channel conditions compared to existing solutions.